Boxing training device for measuring and quantifying the relationship between the force and timing of punches

ABSTRACT

A boxing training device having a first housing and at least a second housing spaced from the first housing. A first sensor is disposed in the first housing for sensing movement of the first housing and outputting a first signal as a function of the sensed movement. At least a second sensor is disposed in the at least second housing for sensing movement of the second housing and outputting a second signal as a function of the movement sensed by the at least second sensor. A system, including the first and at least second sensor, determines as a function of the first signal and second signal, the force of an impact to a bag which impact causes movement of at least one of first or second housing; and displays the force of the impact.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional patent Application No. 61/334,429 filed May 13, 2010, in the entirety hereby incorporated by reference.

BACKGROUND OF THE INVENTION

This application is directed to a boxing training device, and more particularly, a device that provides feedback to a boxer utilizing a heavy bag with respect to the speed and power of punches that are applied in combination.

In 2007, the University of Manchester attempted to measure the punching force of boxer Ricky “The Hitman” Hatton. The Project was headed by Dr. Qingming Li. The measurement was obtained by placing load sensors on the punching and having Mr. Hatton punch them. A high-speed camera was used to record his punches. This data was used to estimate the velocity at which he was punching. This however, was a one-time experiment. As a result, the load sensors do not have to endure the constant shock for years to come. The sensors for the Ricky Hatton experiment were not able to keep up with the amount of force being exerted upon them and the final measurements were estimated from previous data.

“Punching Bag Dynamometer” by Y. Fortin, M. Lamontagne, and A. Gadouas described punching force measurement. The system used however, was (much like the system used by the University of Manchester to measure Mr. Hatton's punching force) not meant to be commercialized and it was in-fact a prototype meant to be used only for that particular experiment. The system they used combined accelerometers with a pressure transducer inside the bag requiring a bag redesign.

The system used the various sensors to correlate data between the accelerometers and the pressure changes being observed in the bag. After calibrating these measurements, they used a simple filtering algorithm in order to remove the noise generated by gravity. The problem with their system was that it used a water bag in order to make the pressure transducer effective. Water bags are not rigid enough to punch and it makes the boxer work harder.

Another known system was known from Pediatric Dynamometer by Patrick Duggan under advisor Dr. Jay Zemel. This system used a piezoelectric material (namely piezoelectric polyvinylidene difluoride) placed inside the soles of children's shoes. This allows the children to wear the shoes as they would any other, while allowing the monitoring of the kinetic activity of the children.

According to this paper, they can be used to measure force. Not only will it not need the use of a power supply to power the sensor, but it would be thin enough to cause little to no disturbance to the boxer. The relation that was setup for this experiment was the following:

F_(y) ∼ Q_(z) F_(y) ∼ ∫_(t_(begin))^(t_(end))I * t = ∫_(t_(begin))^(t_(end))V/R * t

Where:

F_(y): Force measured Q_(z): Total Number of electrons

I: Current V: Voltage Difference R: Resistance of the Film

The designs made by Mr. Duggan were simple enough, the wiring required for the sensor was minimal. If the sensor could be obtained to be big enough to cover the entire bag, it would only require minimal amount of wiring to create the entire setup. The designs presented show that the whole sensor setup does not take up much space.

The results from this experiment showed that there was a high correlation between the force placed upon the system and the voltage reading being obtained from the measuring devices. However, there are certain conditions for which these sensors work great, but for a punching bag this is not true.

Accordingly, it is desirable to develop a product that overcomes the deficiencies of the prior art.

BRIEF SUMMARY OF THE INVENTION

A rigid pipe, has a first housing at one end and a second housing at the opposed end of the pipe. A first accelerometer is disposed within the first housing. A second accelerometer is disposed within the second housing. A processor receives input from each accelerometer and determines the force applied to the bag and the time at which the impact occurred as a function of acceleration sensed at each accelerometer. The processor may also include a clock for determining a time interval turn in which the accelerometers will detect all impacts to the bag or the elapsed time between successive impacts. A display is provided for displaying at least the force of the at least one impact.

In a preferred embodiment, the first housing is disposed at a rotational angle about the pipe relative to the second housing. In a preferred embodiment, each impact, as sensed by the accelerometers is time stamped by the processor during the interval. The processor calculates the force of each individual impact, the number of impacts sensed during the time interval, the spacing in time between respective impacts during the interval and an overall force amount equal to the sum of the force of each impact during the interval.

Specifically, the accelerometers found in this system provide a voltage signal as a function of acceleration to the controller which determines how much acceleration the accelerometers are subjected to. This can be used to measure the force being applied on the system. The signal provided however, is simply a voltage.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described by way of example, with reference to the accompanying drawings, where like numerals are used to denote like elements and in which:

FIG. 1 is a side view of a sensor system for a boxing training device constructed in accordance with the invention;

FIG. 2 is a graphical representation of the sensor operation for a boxing training device constructed in accordance with the invention;

FIG. 3 is a sectional view of a housing holding a sensor in accordance with the invention;

FIG. 4 is a schematic view of a punching bag utilizing the boxing training device in accordance with the invention;

FIG. 5 is a schematic view of the boxing training device constructed in accordance with the invention; and

FIG. 6 a front plan view of a display operating in accordance with the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference is made to FIG. 1 wherein a system, generally indicated as 10, is designed to be inserted inside a punching bag. This means that system 10 must have the ability to push through the punching bag's filling. For this reason, the system is preferably as small as possible, in order to allow the user to insert it into the punching bag with minimum effort, because the sand or rags that fill the punching bag provide a large resistance. Also, system 10 should not materially affect the structure or operation of the punching bag.

System 10 includes a pipe 12. A first housing 14 is affixed at a first end of pipe 12. A second housing 16 is affixed at an opposed end of pipe 12 so as to be spaced from housing 14. A first accelerometer 18 is mounted within housing 14 and a second accelerometer 20 is mounted within second housing 16. See FIG. 3. A second pipe 22 may be used in a preferred, but nonlimiting embodiment, and is affixed to either one of housing 16, 18 to act as a handle to place the system 10 sufficiently within the bag. Pipes are preferred to provide housing for any necessary wiring within system 10, but rods which are resistant to impact may also be used.

It is important to note that the two housings 16, 18 are rotated (rotationally offset about the axis of pipe 12) at an angle relative to each other. In a preferred nonlimiting example, the angle is about forty five degrees. The reason for this, is that it allows the sensors (accelerometers 20) to produce a better reading. The accelerometers 20 measure accelerations in the X and Y directions, therefore, if the two sensors 20 are offset at about forty five degrees relative to each other, then they can measure in four directions. Each accelerometer 20 (Analog Devices ADXL 321 EB are used in a preferred embodiment) can measure in two directions orthogonal to each other. Placing them at the specified angle, successfully changes this to four directions. Were they placed in the same orientation to each other, the measurement would be redundant. In this configuration, as shown in FIG. 2, the system can measure in a total of eight planer directions.

In spite of the fact that these accelerometers can only measure accelerations on a two dimensional plane, when arranged carefully, they can account for forces in almost any direction, as shown in FIG. 2. This positioning increases the signal to noise ratio of system 10 by allowing the accelerometers 18, 20 to have a better probability of measuring the forces through the line of action. This results in better accuracy. The sensors 18, 20 are capable of each measuring an F_(x) and F_(y) which may be normalized by:

F ₁=√(F ² _(x1) +F ² y ₁)  (1)

F ₂=√(F ² _(x2) +F ² y ₂)  (2)

Then in a preferred nonlimiting embodiment, the average between F₁ and F₂ is taken to be the measurement.

A known force must be applied in order to know what voltage the accelerometers are seeing. An example of this would be the following, when the system is struck by a user, a processor operating on the accelerometer signals may display a number based on the accelerometer's data. Example, it may display ˜523. This however, is a meaningless number because it has no units. In order to correct this, a calibration process is required. Because it is known that the change in momentum over the change in time is the definition of force, it becomes possible to calculate how much force was input to the system based on how quickly the momentum of the punching bag changed. After repeating this procedure various times, the calibration can be completed.

As seen in FIG. 3, housing 16 (housing 14 being identical in structure so like numbers are utilized to indicate like structures) in which the accelerometers will sit, formed in a nonlimiting embodiment, has slots 30 to receive a plate 32. This allows accelerometer 20 to be in a natural position. Because the accelerometers 20 used in the preferred embodiment are bi-axial, it is important to have them in their correct position. In one embodiment, Tri-axial, may be used and may be placed in practically any position, however, this would require processing six signals instead of four, which would have in turn caused the system to run slower.

The Housing 16 is then placed inside the punching bag (see FIG. 4), the sand, and/or rags inside the bag, would then sustain the system in place. FIG. 3 is a sectional view of a sensor construction in accordance with the invention. Housing 16 is shown by way of example, the internal structure of housing 18 being substantially identical. The second accelerometer 20 will be separated from the first accelerometer 20 by pipe 12, which in one exemplary nonlimiting example, is about ten inches long and half an inch in diameter. In one embodiment, the pipe is made of galvanized steel and has a threaded terminal at the end, this allows it to connect to another thread on a unit similar to housing 16.

A boxer may often create punching forces in excess of half a ton (1,000 lbf). Therefore, system 10 is designed to be placed within the bag so that the sand (or rags sometimes) that fill the punching bag will act as a damper for the punches that a user could exert. However, there is no complete way to calculate the damping that is created by the rags and the sand inside the bag. A mathematical model was created to account for the damping effect of the filling of the bag.

In one exemplary, but nonlimiting embodiment, galvanized steel was used to hold accelerometer 20 in place, as well as to connect to the pipes 12, 22. Aluminum may also be used to reduce cost. Furthermore, aluminum is easier to machine than steel, as it can be machined at a much higher rate. Because aluminum is much softer than steel, it can easily be machined with high speed steel end mills (which are the most readily available and lowest priced).

There is no way to know exactly what magnitude or direction the force will be applied to system 10, as people with many different body heights, strengths and/or techniques, are expected to hit system 10 from many different directions. For this reason, the calculations were carried out assuming a worst case scenario, meaning that there was no damping present to absorb the blows of the user, and that the user was striking the punching bag with a force of 1,000 lbf. If the entire force of the boxer were concentrated on just one spot, in this case the housing, then the stress would be as follows.

$\sigma = {\frac{F}{A} = {\frac{1,000}{0.0195} = {51,287\frac{lbf}{{ft}^{2}}}}}$

In this embodiment, the yield strength of 6061 aluminum is 57,600 lbf/ft2, therefore, system 10 is well within the yield point, even when no damping effects are considered. This means that even if the absolute worst situation is considered, the factor of safety is still 1.12. In this embodiment, the pipes 12, 22 are made of aluminum, and therefore, the weakest structurally as the other components are preferably made of steel.

While this approach is only an approximation, and not directly applicable to this system, the system can be closely approximated by treating it as a simply supported beam. The pipes 12, 22 and housings 14, 16 for this case are ignored, and the entire system 10 is treated as an entire beam. The reason for this is that there is no specific equation available to treat the junction of a pipe and a pressure fitting under transverse loading. The equation used when this omission is made is the following.

$\delta = \frac{{PL}^{3}}{48{EI}}$

Where E=Modulus of Elasticity I=Moment of Inertia

This equation gives the maximum deflection of the pipe 12, which in this case would be at the center. The deflection at any arbitrary point however, is given by the following equation.

$y = {\frac{Px}{12{EI}} \times \left( {\frac{3l^{2}}{4} - x^{2}} \right)}$ for  0 < x < 1/2

Finally, the slope at the end of the pipe is given by the following equation.

$\theta_{1} = {\theta_{2} = \frac{{Pl}^{2}}{16{EI}}}$

A maximum deflection that the system experiences when a one thousand pound force is applied directly on it, can be determined utilizing software products such as CosmosWorks. The maximum deflection was calculated as about 0.000762 inches.

The maximum deflection was again calculated using a second software product, ANSYS work bench, which resulted in a deflection of only about 0.00036 inches. From comparing the data between both methods, the two calculated deflections are extremely close. The difference between the two is about 0.0004 inches. From these analyses it can be seen that deflection is not a critical issue for the design since it is so small.

To mimic the bending stresses created by the punching through a damping system, a Finite Element Analysis was carried out to find the maximum stress factor of safety that the system would have to withstand. In order to simulate the system it was assumed that one side would be fixed, which is similar to the case of a trainer holding the punching bag for the boxer. A mesh element size of 0.11669 was used for both programs to calculate the data.

Von Mises yield criterion were used to calculate the stresses throughout the system. Von Mises stress is determined from the stress state as:

σv=√[1/2((σ_(x)−σ_(y))²+(σ_(y)−σ_(z) ²)+(σ_(z)−σ_(x))²)+3(T ² _(xy) ⁺ T ² _(yz) ⁺ T ² _(zx))]

Where

σ_(x), σ_(y), σ_(z)=Principal Stresses

T_(xy), T_(zy), T_(xz)=Shear Stresses

The maximum stress calculated using CosmosWorks, is about 13,259.4 psi when applying 1,000 lbs of force. It is important to note that the force sensed by the system will be much lower, because this simulation does not account for the damping effects of the bag construction including the internal sand and rags. As a check, the stress distribution was also calculated using ANSYS Workbench. The maximum stress was calculated to be about 9,916 psi. Comparing to the data from CosmosWorks, it can be seen that the value for CosmosWorks is 3,343.4 psi higher.

The equivalent strain (ESTRN) is calculated by the following equation:

${ESTRN} = {2.0\frac{\left. \sqrt{}ɛ_{1} \right. + ɛ_{2}}{3.0}}$

Where

ε₁=0.5[(EPSX−meanstrain)²+(EPSY−meanstrain)²+(EPSZ−meanstrain)²]

ε₂=0.25[GMXY ² +GMXZ ² +GMYZ ²]

meanstrain=(EPSX+EPSY+EPSZ)/3

Where

EPSX=Normal strain in the X-direction EPSY=Normal strain in the Y-direction EPSZ=Normal strain in the Z-direction GMXY=Shear strain in the Y direction in the plane normal to X GMXZ=Shear strain in the Z direction in the plane normal to X GMYZ=Shear strain in the Z direction in the plane normal to Y

The strain calculated by the CosmosWorks and ANSYS work bench applications is 0.000393 and 0.000342 respectively.

Both programs used the Von Misses failure criterion to determine the factor of safety. The factor of safety must be equal or greater than one, in order to be considered a safe design. The following equation is used to calculate the factor of safety.

FOS=σ_(limit)/σ_(vonMises)

Where

σ_(limit)=Ultimate Tensile Strength

CosmosWorks calculated the factor of safety to be 2.31 at the most critical point, and ANSYS calculated 3.66. To be safe, even though both succeed by being greater than one, 2.31 is used for the design as a guideline.

Although the housing 14, 16 for this system is not a complex mechanical system, it is by far the most complex of all the components in the system. This housing 14, 16 must ensure a proper fit of the system, as well as to ensure that as little material as possible went to waste. In a preferred nonlimiting embodiment, housing 14, 16 is created by die casting, as it is small enough where this procedure could be used. This allows production to be very fast, and it also saves all the material that would have to be discarded if the part were machined from a billet piece of aluminum. In order to die cast this component, in a nonlimiting preferred embodiment, a volume of aluminum of 0.941 in³ is required. The cost for this amount of aluminum (for almost any grade) is very little.

The accelerometers chosen in a nonlimiting exemplary embodiment are Analog Devices model ADXL321, manufactured by Analog Devices. These accelerometers were chosen for various reasons. The first reason for selecting these accelerometers is that they are very accurate when compared to other accelerometers. These accelerometers have an error of only ten percent, which is very good for an accelerometer. The reason that these evaluation boards were used as opposed to simply buying the accelerometer is that the accelerometers come with no electronic components. These accelerometers require various capacitors and resistors to be connected in the circuitry in order to function properly.

The accelerometer 20 provides an output to a microcontroller 33. The processor 33 selected, by way of nonlimiting exemplary embodiment, was the Arduino Duemilanove microcontroller, which is a commonly available microcontroller. It was selected because it provides all the speed and memory necessary to control system 10. The Arduino microcontroller also has the advantage over others in ease of programming. There are other microcontrollers 33 such as the PICKit microcontroller which would operate in accordance with the invention, but which are more difficult to program.

Because system 10 is very different from anything that is currently available in the market, the housings 14, 16 for the accelerometer 20 had to be custom designed. Each housing 14, 16 was custom built from T5 aluminum in a nonlimiting exemplary embodiment.

The housings 14, 16 in system 10 preferably, by way of nonlimiting example, are connected by about a 10 inch long section of steel pipe 12 that is 1/16 inch in thickness. Above one housing 16, there is another section of pipe 22. Pipes 12, 22 are preferably hollow to provide a housing for wires (not shown) interconnecting accelerometers 20 in housing 14, 16 to processor 34.

In a preferred nonlimiting embodiment, a more efficient design allows the use of bi-axial accelerometer 20 instead of tri-axial accelerometers, and a forty five degree offset is provided between the two accelerometer 20. The accelerometers measure forces at ninety degrees to each other. By placing the accelerometers at forty five degrees to each other, these angles would be decreased to forty live degrees (as opposed to ninety). This small alteration makes the system redundant.

The brain of system 10 is processor 34. Microcontroller 33 provides the excitation voltage to the accelerometers 20, the accelerometers 20 then return an analog signal to microcontroller 33. Microcontroller 33 then converts this analog signal into a digital voltage signal corresponding to movement as a function of outputs from both accelerometers 20. The signal is then wirelessly transmitted to processor 34, preferably a standard laptop with an application loaded thereon, to be recorded, processed and displayed. In one preferred, but nonlimiting embodiment, ZigBee protocols may be used with radio frequency (RF) transceivers such as 35 XBee chips to provide communication between microcontroller 33 and processor 34. However, processor 34 may be wired to microcontroller 33.

Reference is now made to FIGS. 4 and 5 in which the overall boxing training device 30 is shown. In FIG. 4, it is understood from the previous explanation that system 10 is the sensor system for the overall boxing training device 30 and is inserted within a heavy bag 60, the heavy bag 60 being constructed as known in the art. Pipes 12, 22 extend within bag 60 substantially along the longitudinal axis of bag 60 during use. Microcontroller 33 and radio frequency transceiver 35 may extend outside of heavy bag 60 in a preferred embodiment. However, with a sufficiently powerful transmitter, microcontrollers 33 and RF transceiver 35 may also be disposed within bag 60.

As seen in FIG. 5, system 30 includes the sensor system 10 and microcontroller 33 and RF transponder 35 as discussed above wirelessly communicates with a processor 34 through a radio frequency transponder 37 communicating with processor 34. As seen in FIG. 5, processor 34 includes an internal clock 38, operates on data stored in database 36 and, as will be discussed in greater detail below, provides an output to drive a display 40.

Processor 34 converts the acceleration signal output by microcontroller 33 into an applied force value, such as pounds, utilizing either an algorithm or look up table stored in a database 36. The determined force is stored by processor 34 in database 36. Processor 34 includes a clock 38. Clock 38 is a running clock and processor 34 utilizes clock 38 to determine a start and stop interval for an overall time as well as for the timing between each punch sensed by sensor 32. Processor 34 stores the overall interval information as well as the time between punch information in database 36. Processor 34 processes the data stored in database 36, such as the force applied with each punch, the overall force sensed during the entire interval, counts the number of punches during an interval, and associates an elapsed time between a previous punch and the current punch or impact.

Processor 34 outputs a display signal to display 40 for displaying the information determined by processor 34. Display 40 may be any display, mechanical, electrical, visual or audio capable of communicating the information output by processor 34 to the user.

Reference is now made to FIG. 6 in which a preferred, non-limiting exemplary embodiment of display 40 is provided. In this embodiment display 40 is a visual display having hit display region 42 indicating the force of each of a successive number of hits; up to eights hits in this example, time displays 44 displaying an elapsed time between successive hits so that there are displays 44 of time intervals T1-T7.

Furthermore, as discussed above, processor 34 may determine a total number of hits for a total count, which is displayed at a total count display 46. Similarly, a total time interval as measured by processor 34 is displayed at a total time display 48. Processor 34, utilizing the raw data from microcontroller 33 for hits H1-H8, calculates a total force and outputs that amount as a total force display 50. Lastly, processor 34 utilizes an algorithm for processing the data to determine a score which may be a function of interval times T1-T7 and total force, total time and total force, or individual times and force for the respective number of hits H1-H8. For example, consistent force among punches or increased force and shortened timing between intervals may be the goal and processor 34 determines a score for the completed time interval as a function of the scoring algorithm which is then displayed at a total score display 52 within display 40.

Furthermore, display 40 may be an LCD panel, a touch screen, a loud speaker, a mechanical display with a rotating wheel and cog configuration, or any type of display capable of displaying individual hits, counts and/or the recorded times.

It should be understood that given the state of technology with microcontrollers and microprocessors, that the functionality among microcontroller 33, radio frequency transponders 35, 37 and processor 34 can be found almost entirely in processor 34, almost entirely in microcontroller 33, or divided therebetween. Furthermore, it may also be understood that the entire system may be integrated into a heavy bag so that display 40 is provided on the bag for convenient real time feedback to the user.

Furthermore, in a preferred embodiment, display 40 is the screen of a laptop computer. However, display 40 may also be an input/output device such as a tablet computing device, such as a touch screen capable of allowing the programming of processor 34 to instruct processor 34 regarding the mode in which it is to operate as well as to set the parameters for the number of hits to be recorded and/or the time interval.

It should also be noted that displays 42 and 44 need not be fixed but in fact may correspond to the scores of any number of recorded hits and time intervals so that if a time interval is being measured as the time needed to deliver 15 hits, the display, if operating in this reporting mode, would show 15 hit values and 14 time interval values.

During operation, a user would input a start command by hitting a start button 60 somewhere on the apparatus, preferably display 40. Display 40 may then prompt the user for an overall time interval or overall punch count interval to be monitored. An input may be selected for a mode to select the proper algorithm for the total score output as a function of the desired result whether it is speed, consistency, or power, or a combination of at least two of the three. For example, the user may enter a total accrued force goal.

In a preferred embodiment, the clock would actually begin with the first sensed impact after start input 60 had been activated. A boxer punches the bag. Accelerometers 18, 20 measure the movement and outputs voltage signal to microcontroller 33 which sends a voltage signal as function thereof to processor 34. Processor 34 notes the clock and uses the voltage to calculate the force and stores both in database 36.

Processor 34 may send a real time force signal to display 40 or a delayed time and force signal to display 40 so that the user may have real time feedback regarding each of the punches. As a second punch is sensed, the process is repeated.

Processor 34 samples clock 38 to determine an elapsed time interval and stores either the elapsed time interval or the raw (gross) clock reading along with the force of the second punch in database 36 for later calculations. This process is repeated until either the desired number of punches, goal of accrued force, or the desired elapsed time has occurred. The sensor is then disabled, i.e., processor 34 no longer operates on its inputs and the displays as discussed above such as total count, total time, total force and/or total score along with the individual values of each punch are provided.

In one embodiment to help achieve goals, a user may input at display 40, a minimum force threshold which processor 34 stores in database 36. During training, processor 34 compares the force of each sensed impact and compares the sensed force to the minimum force threshold. Processor 34 will ignore any impact which does not equal or exceed the minimum force threshold when displaying hits, computing hit intervals and/or computing an overall score.

It is well understood by a boxer that a heavier boxer will usually be able to apply more force to a punch than a lighter boxer. Therefore, there are often debates regarding who is the best boxer “pound for pound”. In another embodiment, processor 34 normalizes the scores of each user by multiplying the force of the sensed impact by a nominal weight divided by the actual weight. In an exemplary embodiment, the nominal weight is 150 so that a boxer weighing less than 150 is given credit for impacting the bag with a greater force than a boxer at 150 pounds or greater even if the sensed impact is equal. Conversely, a boxer weighing more than 150 will be credited with only a fraction of the force attributed to the same impact by a boxer weighing 150 or less. Normalization may also be performed as a function of gender by indicating to processor 34 the gender of the user. An adjusted or normalized score is displayed at display 40 as an adjusted score to indicate to the user an indication of efficiency.

By utilizing the normalization calculation, enables users to compare scores. An input is made at display 40 to indicate to processor 34 a first user and a second user. Processor 34 stores the hits of a session and overall score of a first user in database 36. The identity of the second user is input at display 40 and processor 34 stores the results of the second session associated with a second user in database 36. Processor 34 displays both the session associated with the first user and the session associated with the second user by displaying any one of total score, force for each impact, and interval between each impact for the first user and second user as a comparison at display 40. Alternatively, processor 34 may display a comparison on an impact by impact basis in real time as the second user performs their session as a way to incentivize the second user. Each user may enter their weight at display 40 to be stored in database 36. Processor 34 calculates an actual score or normalized score for each user as a head to head comparison.

Similarly, processor 34 may store each session for an individual user. Each round may be identified with a user identification and time stamp. In this way, a user may cause processor 34 to display the last 10 sessions in time for that particular user. Furthermore, each round is provided with a raw score as discussed above. Processor 34 calculates which sessions have the highest score so that the 10 highest scores may be displayed. Additionally, much as processor 34 displayed comparisons between two competing users, a user may select a session from either the chronological list or best list to be used as a comparison to a current session as described above.

As discussed above, it is possible in one embodiment of the invention to input a minimum threshold force to be stored in database 36. Similarly, one can input a minimum threshold time interval, Processor 34 compares each impact and each time interval to the minimum threshold values as stored in database 36. As each impact is made, the force of that impact is displayed. However, if the impact is within 10% of the threshold level, the force level is displayed utilizing a first color such as yellow. If the impact force is more than 10% less than the desired level, then the force value is displayed in a different color such as red. If the force value is more than 10% greater than the desired value, then a third color such as green may be utilized to indicate this fact at display 40. Similarly, if the speed of the successive impacts, i.e. the time interval is more than 10% less than a desired value, it is displayed in green, if within 10% of the desired value, it is displayed in yellow, and if more than 10% greater than the desired value, the value is displayed in red. In this way, feedback is provided in real time to a user regarding its target goals.

Lastly, energy is substantially directly correlated to force. Knowing the time interval, the overall force and the weight of a user, processor 34 calculates the calories expended by a user. The calories burned during a session are then displayed at display 40.

It should be noted that punching the bag was used as the most common example. However, all that is really being measured is acceleration so that any impact such as from a foot, or any other body part such as in a martial art's use can also be processed.

Thus, while there have been shown, described and pointed out novel features of the present invention as applied to the preferred embodiments thereof, it will be understood that various omissions and substitutions and changes in form and detail are contemplated so that the disclosed invention may be made by those skilled in the art without departing from the spirit of the invention. It is the intention therefore to be limited only as indicated by the scope of the claims appended hereto. It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention, which is a matter of language, might be said to fall therebetween. 

1. A boxing training device comprising: a first housing; at least a second housing spaced from the first housing; a first sensor disposed in the first housing for sensing movement of the first housing and outputting a first signal as a function of the sensed movement; at least a second sensor disposed in the at least second housing for sensing movement of the second housing and outputting a second signal as a function of the movement sensed by the at least second sensor; a system, including the first and at least second sensor, the system for determining, as a function of the first signal and second signal, the force of an impact to a bag which impact causes movement of at least one of first or second housing; and displaying the force of the impact.
 2. The boxing training device of claim 1, wherein said first housing and at least second housing are each adapted to be inserted into a heavy bag.
 3. The boxing training device of claim 1, wherein the system includes a processor receiving a voltage signal, generated as a function of the first signal and the second signal, indicative of sensed movement; the processor converting a value of the voltage to a force value; and a database associated with the processor; and a display, the processor performing at least one of displaying the force value at the display and storing the force value in the database.
 4. The boxing training device of claim 1, wherein at least one of the first sensor and at least second sensor is an accelerometer.
 5. The boxing training device of claim 1, wherein said first housing is connected to said at least second housing.
 6. The boxing training device of claim 1, wherein the first housing is rotationally offset relative to the at least second housing.
 7. The boxing training device of claim 6, wherein the offset is about 45 degrees.
 8. The boxing training device of claim 3, wherein the processor stores a threshold force value.
 9. The boxing training device of claim 8, wherein the processor displays the force value at the display when the force value is greater than or equal to the threshold force value.
 10. The boxing training device of claim 8, wherein the processor compares the force value to the threshold force value and causes the display to display the force value in a first color if the force value is less than a predetermined percentage of the threshold force value, display the force value at the display in a second color if the force value is within a predetermined percentage of the threshold force value; and display the force value in a third color if the force value is greater than a predetermined percentage of the threshold value.
 11. The boxing training device of claim 3, further comprising a clock, the processor receiving a clock input from the clock, a first voltage signal and a second voltage signal and determining an elapsed time between the first voltage signal and the second voltage signal.
 12. The boxing training device of claim 3, wherein the processor determines a score as a function of the force and the elapsed time between at least a first voltage signal and a second voltage signal.
 13. The boxing training device of claim 12, wherein the processor stores a force value at least for two voltage signals and an elapsed time interval between the occurrence of the two or more voltage signals for a first predetermined time period.
 14. The boxing training device of claim 3, wherein the processor normalizes the force value.
 15. The boxing training device of claim 14, wherein the processor normalizes the force value by dividing a normalization weight by the weight of a user to obtain a normalization value and by multiplying the normalization value by the force value. 